Methods and apparatus for serving relevant advertisements

ABSTRACT

The relevance of advertisements to a user&#39;s interests is improved. In one implementation, the content of a web page is analyzed to determine a list of one or more topics associated with that web page. An advertisement is considered to be relevant to that web page if it is associated with keywords belonging to the list of one or more topics. One or more of these relevant advertisements may be provided for rendering in conjunction with the web page or related web pages.

RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication Ser. No. 60/413,536, filed on Sep. 24, 2002, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] A. Field of the Invention

[0003] The present invention relates generally to advertising and, moreparticularly, to serving relevant advertisements by comparingadvertisers' targeting criteria to the content of media on which theadvertisements are to be published.

[0004] B. Description of Related Art

[0005] Advertising using traditional media, such as television, radio,newspapers and magazines, is well known. Advertisers have used thesetypes of media to reach a large audience with their advertisements(“ads”). To reach a more responsive audience, advertisers have useddemographic studies. For example, advertisers may use broadcast eventssuch as football games to advertise beer and action movies to a youngermale audience. However, even with demographic studies and entirelyreasonable assumptions about the typical audience of various mediaoutlets, advertisers recognize that much of their ad budget is simplywasted because the target audience is not interested in the ad they arereceiving.

[0006] Interactive media, such as the Internet, has the potential forbetter targeting of advertisements. For example, some websites providean information search functionality that is based on query keywordsentered by the user seeking information. This user query can be used asan indicator of the type of information of interest to the user. Bycomparing the user query to a list of keywords specified by anadvertiser, it is possible to provide some form of targetedadvertisements to these search service users. An example of such asystem is the Adwords system offered by Google, Inc.

[0007] While systems such as Adwords have provided advertisers theability to better target ads, their effectiveness is limited to siteswhere a user enters a search query to indicate their topic of interest.Most web pages, however, do not offer search functionality and for thesepages it is difficult for advertisers to target their ads. As a result,often, the ads on non-search pages are of little value to the viewer ofthe page and are therefore viewed more as an annoyance than a source ofuseful information. Not surprisingly, these ads typically provide theadvertiser with a lower return on investment than search-based ads,which are more targeted.

[0008] It would be useful, therefore, to have methods and apparatus forproviding relevant ads for situations where a document is provided to anend user, but not in response to an express indication of a topic ofinterest by the end user (e.g., not responsive to the end usersubmitting a search query).

SUMMARY OF THE INVENTION

[0009] Systems and methods consistent with the present invention addressthis and other needs by identifying targeting information for anadvertisement, analyzing the content of a target document to identify alist of one or more topics for the target document, comparing thetargeting information to the list of topics to determine if a matchexists, and determining that the advertisement is relevant to the targetdocument if the match exists.

[0010] Additional aspects of the present invention are directed tocomputer systems and to computer-readable media having features relatingto the foregoing aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate an embodiment of theinvention and, together with the description, explain the invention. Inthe drawings,

[0012]FIG. 1 is a diagram illustrating an environment within which theinvention may be implemented;

[0013]FIG. 2 is a diagram functionally illustrating an advertisingsystem consistent with the invention;

[0014]FIG. 3 is a diagram illustrating apparatus with which theinvention may be implemented;

[0015]FIG. 4 is a flow diagram of an exemplary method for providingrelevant advertisements, consistent with the present invention; and

[0016]FIG. 5 is a sample target document.

DETAILED DESCRIPTION

[0017] The following detailed description of the invention refers to theaccompanying drawings. The detailed description does not limit theinvention. Instead, the scope of the invention is defined by theappended claims and equivalents.

[0018] The present invention involves methods and apparatus fordetermining advertisements that are relevant to a given document. In oneimplementation, the document is a web page and the advertisements areelectronic files that are capable of being rendered on that web page. Aset, such as a list, of topics corresponding to the web page isgenerated by analyzing the content of the web page. There are a varietyof techniques by which this may be performed, one of which is bycomputing a term vector for the web page and selecting the top N termsfrom that vector. The list of topics is compared to target informationassociated with the advertisements (e.g., keywords specified for theadvertisements) to determine which of the advertisements are relevant tothe web page. Some or all of these relevant advertisements may then beassociated with the web page so that they may be rendered (e.g.,displayed) with the web page.

[0019] Those skilled in the art will recognize that many otherimplementations are possible, consistent with the present invention.

[0020] A. Environment and Architecture

[0021]FIG. 1 is a diagram illustrating an environment within which theinvention may be implemented. The environment includes an advertiser110, an advertising system 120, an advertisement consumer 130, and anadvertising target 140.

[0022] Advertiser 110 may be the party that directly sells the goods orservices being advertised (e.g., Amazon.com) or an agent authorized toact on the advertiser's behalf. The advertisement desired by advertiser110 may exist in a variety of forms ranging from standard printadvertisements, online advertisements, audio advertisements,audio/visual advertisements, or any other type of sensory messagedesired.

[0023] Advertising system 120 interfaces with both the advertiser 110and the advertisement consumer 130. It may perform a variety offunctions, as explained in more detail below in reference to FIG. 2.Thisinvention may be used with such an advertising system 120.

[0024] Advertisement consumer 130 is the entity that will issue arequest for advertisements to advertising system 120, obtain theadvertisements from advertising system 120, and present theadvertisement to the advertising target 140. Typically, theadvertisement consumer is the entity that provides the content withwhich the advertisement is to be associated. In one implementation, theadvertising consumer 130 is a search engine, such as that employed byGoogle, Inc. at www.google.com.

[0025] Advertising target 140 is the individual (or set of individuals)who ultimately receive the advertisement. In the case of visualadvertisements, for example, the advertisement target 140 is the personwho views the advertisement.

[0026]FIG. 2 is a diagram functionally illustrating an advertisingsystem consistent with the invention. The system includes an ad campaignentry and management component 210, a tools component 220, a billingcomponent 230, one or more databases 240, an ad consumer interfacecomponent 250, an ad selection component 260, an ad ordering component270, an ad serving component 280, and a statistics engine component 290.If the present invention is to be used with such an advertising system,it will primarily concern ad selection component 260. To help understandthe invention, other components of the advertising system will beexplained below. Furthermore, although FIG. 2 shows a particulararrangement of components constituting advertisement system 120, thoseskilled in the art will recognize that not all components need bearranged as shown, not all components are required, and that othercomponents may be added to, or replace, those shown.

[0027] Ad entry and management component 210 is the component by whichthe advertiser enters information required for an advertising campaignand manages the campaign. An ad campaign contains one or moreadvertisements that are related in some manner. For example, the FordMotor Company may have an ad campaign for zero percent financing, whichcould contain a series of advertisements related to that topic. Amongthe other things that could be provided by an advertiser through adentry and management component 210 are the following: one or moreadvertising creatives (simply referred to as “ads” or “advertisements”),one or more set of keywords or topics associated with those creatives(which may be used as targeting information for the ads), geographictargeting information, a value indication for the advertisement, startdate, end date, etc. The data required for, or obtained by, ad entry andmanagement component 210 resides in one of the databases 240.

[0028] Tools component 220 contains a variety of tools designed to helpthe advertiser 110 create, monitor, and manage its campaigns. Forexample, tools component 220 may contain a tool for helping advertiser110 estimate the number of impressions an ad will receive for aparticular keyword or topic. Similarly, tools component 220 may be usedto help advertiser 110 generate a list of keywords or topics for a givenadvertisement, or to generate additional keywords or topics based onrepresentative ones supplied by advertiser 110. Other possible tools maybe provided as well. Depending on the nature of the tool, one or moredatabases 240 may be used to gather or store information.

[0029] Billing component 230 helps perform billing-related functions.For example, billing component 230 generates invoices for a particularadvertiser 110 or ad campaign. In addition, billing component 230 may beused by advertiser 110 to monitor the amount being expended for itsvarious campaigns. The data required for, or obtained by, billingcomponent 230 resides in a database 240.

[0030] Databases 240 contain a variety of data used by advertisingsystem 120. In addition to the information mentioned above in referenceto ad entry and management system 210, databases 240 may containstatistical information about what ads have been shown, how often theyhave been shown, the number of times they have been selected, who hasselected those ads, how often display of the ad has led to consummationof a transaction, etc. Although the databases 240 are shown in FIG. 2 asone unit, one of ordinary skill in the art will recognize that multipledatabases may be employed for gathering and storing information used inadvertising system 120.

[0031] Ad consumer interface 250 is a component that interfaces with adconsumer 130 to obtain or send information. For example, ad consumer 130may send a request for one or more advertisements to ad consumerinterface 250. The request may include information such as the siterequesting the advertisement, any information available to aid inselecting the advertisement, the number of ads requested, etc. Inresponse, ad consumer interface 250 may provide one or moreadvertisements to ad consumer 130. In addition, ad consumer 130 may sendinformation about the performance of the advertisement back to the adsystem via the ad consumer interface 250. This may include, for example,the statistical information described above in reference to a database240. The data required for, or obtained by, ad consumer interfacecomponent 250 resides in a database 240.

[0032] Ad selection component 260 receives a request for a specifiednumber of advertisements, coupled with information to help select theappropriate advertisements. This information may include, for example, asearch query specified by an end user. Alternatively, or in addition, asdescribed in more detail below, this information may include datarelated to the content of the page for which the advertisements arebeing requested.

[0033] Ad ordering component 270 receives a list of relevant ads from adselection component 260 and determines a preference order in which theyshould be rendered to an end user. For example, relevant ads may beordered based on the value indication associated with each ad. Theseordered ads may be provided to an ad serving component 280.

[0034] Ad serving component 280 receives an ordered list of ads from adordering component 270, and formats that list into a manner suitable forpresenting to ad consumer 130. This may involve, for example, renderingthe ads into hypertext markup language (HTML), into a proprietary dataformat, etc.

[0035] Statistics engine 290 contains information pertaining to theselection and performance of advertisements. For example, statisticsengine 290 may log the information provided by ad consumer 130 as partof an ad request, the ads selected for that request by ad selectioncomponent 260, the order selected by ad ordering component 270, and thepresentation of the ads by ad serving component 280. In addition,statistics engine 290 may log information about what happens with theadvertisement once it has been provided to ad consumer 130. Thisincludes information such as on what location the ad was provided, whatthe response was to the advertisement, what the effect was of theadvertisement, etc.

[0036]FIG. 3 is a diagram illustrating an architecture in which thepresent invention may be implemented. The architecture includes multipleclient devices 302, a server device 310, and a network 301, which maybe, for example, the Internet. Client devices 302 each include acomputer-readable medium 309, such as random access memory, coupled to aprocessor 308. Processor 308 executes program instructions stored inmemory 309. Client devices 302 may also include a number of additionalexternal or internal devices, such as, without limitation, a mouse, aCD-ROM, a keyboard, and a display. Thus, as will be appreciated by thoseskilled in the art, the client devices may be personal computers,personal digital assistances, mobile phones, content players, etc.

[0037] Through client devices 302, requesters 305 can communicate overnetwork 301 with each other and with other systems and devices coupledto network 301, such as server device 310. Requestors 305 may, forexample, be advertisers 110, advertisement consumer 130, or advertisingtarget 140.

[0038] Similar to client devices 302, server device 310 may include aprocessor 311 coupled to a computer readable memory 312. Server device310 may additionally include a secondary storage element, such as adatabase 240.

[0039] Client processors 308 and server processor 311 can be any of anumber of well known micro-processors, such as processors from IntelCorporation, of Santa Clara, California. In general, client device 302may be any type of computing platform connected to a network and thatinteracts with application programs, such as a digital assistant or a“smart” cellular telephone or pager. Server 310, although depicted as asingle computer system, may be implemented as a network of computerprocessors.

[0040] Memory 312 may contain a number of programs, such as thecomponents described above in reference to FIG. 2.

[0041] B. Operation

[0042]FIG. 4 is a flow diagram of an exemplary method for determining ifan advertisement is relevant to a document, consistent with the presentinvention. As used herein, the term “document” includes any type ofpaper or electronic document or file, including audio, video, image,text, etc. That is, as will be appreciated by one skilled in the art, a“document” as used in the specification is any machine-readable andmachine-storable work product. A document may be a file, a combinationof files, one or more files with embedded links to other files, etc. Forthe sake of illustration, it may be understood that the processdescribed herein takes place as part of the ad selection component 260,although those skilled in the art will recognize that it need not takeplace in that component alone.

[0043] The exemplary method is not limited by the order shown in theflow diagram. The process identifies targeting information for anadvertisement. (Stage 410). The targeting information may be in the formof a list of keywords or phrases associated with the advertisement(e.g., “honda”, “honda cars”, “cars”, etc.), as provided by advertiser110 through ad campaign entry and management component 210.Alternatively, or in addition, the targeting information may bedetermined algorithmically, based on the content of the advertisement,the goods or services being advertised, the targeting of other relatedadvertisements, etc. For example, if the content of the advertisementincludes “Buy honda cars at the lowest prices of the year!”, the terms“honda” or “honda cars” may be extracted from that content. Thetargeting information may also include other demographic information,such as geographic location, affluence, etc. Thus, the targetinginformation is simply some information from which a topic may bederived.

[0044] Next, the target document (i.e., the document corresponding towhich a relevant advertisement is requested) is analyzed to identify atopic corresponding to that target document. (Stage 420). The targetdocument may be stored on a database 240 or may be provided by adconsumer 130 via ad consumer interface component 250. There are numerousways in which the target document may be analyzed to identify thistopic, as described below in reference to FIG. 5 and related text.

[0045] The targeting information identified in stage 410 is compared tothe one or more topics identified in stage 420 to determine if a matchexists. (Stage 430). A “match” need not be an exact match. Instead, amatch is an indication of a relatively high degree of similarly, and/ora predetermined (e.g., absolute) degree of similarity. If a matchexists, the advertisement is determined to be relevant to the targetdocument (stage 440) and may be provided to ad ordering component 270,for eventual provision to ad consumer 130 via ad consumer interfacecomponent 250.

[0046] Those skilled in the art will also recognize that the functionsdescribed in each stage are illustrative only, and are not intended tobe limiting.

[0047] One way to identify a topic corresponding to the target documentis by analyzing some or all text within the target document, which shallbe illustrated in reference to FIG. 5. FIG. 5 shows a sample document,entitled “Travels in Italy”, which contains a collection oftravel-related information pertaining to Italy. The document textcontains the term “restaurant” (appearing 20 times), “chianti”(appearing 10 times), and “the” (appearing 100 times). It could bedetermined that one or more of each term (word or phrase) that appearsin the title of the target document corresponds to a topic of the targetdocument. On this basis, the topics for this document may be “travels”,“in”, and/or “italy.”

[0048] Alternatively, it could be determined that one or more of eachterm that appears in the body of the target document corresponds to atopic of the target document. In the simplest case, each term within thetarget document would be identified as a topic. A slightly more complexapproach would be to identify a term as a topic if it appears in thetarget document more than N times, such as N=2 (and indeed such athreshold-based approach could be used whenever terms within text arebeing analyzed). Even more complex analysis could be performed, such asby using a term vector for the target document, which assigns weights toeach term. For example, terms that appear frequently in the targetdocument may be assigned a relatively higher weight than those thatappear less frequently. And so the term “the” would have a higher weightthan “restaurant”, which would have a higher weight than “chianti”.

[0049] In addition, the weighting could be adjusted to give higherweight to terms that appear less frequently in a collection, such as acollection to which the document belongs or the general collection ofdocuments. For example, the term “chianti” does not appear very commonlyacross the general collection of documents and so its weight may beboosted. Conversely, the term “the” appears so frequently across acollection of documents that its weight may be reduced or eliminatedaltogether.

[0050] In any situation where terms within text are assigned weights orscores, those resulting scores may be used to determine which terms willbe identified as topics for the target document. For example, it may bedetermined that only the top scoring term would constitute a topic forthe target document. Alternatively, or in addition, it may be determinedthat the top Z terms (or a subset thereof) will constitute topics forthe target document, with Z being some defined number. Alternatively, orin addition, it may be determined that terms having a score that exceedsY (or a subset thereof) will constitute topics for the target document,with Y being some defined number. Thus, as one skilled in the art willappreciate, topics may be determined based on absolute and/or relativecriteria.

[0051] Alternatively, or in addition to using text or other informationwithin the target document, meta-information associated with the targetdocument may be used. For example, a reference to the target document byanother document may contain a brief description of the target document.Assume a document called “Entertainment” that contains a reference tothe target document and describes it as “For a description ofrestaurants and wine in Italy, see ‘Travels in Italy’.” In the contextof a web page, this is often described as anchor text. One or more suchbrief descriptions may be used to revise (figuratively) the targetdocument by supplementing or replacing some or all of its content withthe brief descriptions. So, for example, the topic could be identifiedfrom the combination of the target document's title and the briefdescriptions of the target document.

[0052] Alternatively, or in addition to the brief descriptions fromthese references, the references themselves may be used. For example, areference from another document to the target document may be used as anindication that the two documents are similar. Alternatively, or inaddition, a reference from the target document to another document maybe used as an indication that the two documents are similar. So areference between the “Entertainment” document and the “Travels inItaly” document may indicate that the two are related. In the context ofweb pages, these references occur in the form of links from one web pageto another. On this basis, the content (or meta-information) of theother document may be used to revise (figuratively) the target documentby supplementing or replacing its content with that of the otherdocument. The revised target document's content may then be analyzedusing the techniques described above to identify one or more topics.

[0053] Alternatively, or addition to using the content (includingperhaps metadata) associated with a target document, other techniquesmay be used to identify one or more topics for the target document. Forexample, the top N queries (or subset thereof) that result in areference to the target document could be determined to constitute atopic for the target document, with N being some defined number. Thesemay be, for example, text queries in a search engine that yield a resultthat links to the target document or web page. Alternatively, or inaddition, the content of other similar documents (e.g., in the samecollection as the target document, in the same category as the targetdocument, etc.) may be used to revise (figuratively) the content of thetarget document. Any of the techniques described above may then be usedto analyze the target document to identify one or more topics. In thecontext of web pages, this may be other web pages that are stored withina subdirectory of related pages on the same host as the target web page.Alternatively, or in addition, any technique for classifying the targetdocument into a set of one or more topics or categories may be used.Even the search query history of one or more users who visit the targetdocument (or target web page) may be used to identify a topic for thetarget document or web page, on the theory that a visit to the targetdocument that is temporally proximate to that search query historyindicates that the user thought the concepts were related. For example,if a user searched for “italian wine” and then soon afterwards visitedthe “Travels in Italy” document, the content of that prior search couldbe used to determine that “italian” and/or “wine” are potential topicsfor the “Travels in Italy” document.

[0054] Using one or more of the various techniques described above, orother techniques, one or more topics may be identified for the targetdocument. Once these topics have been identified, a variety oftechniques may be used to determine other topics that are related tothose identified topics. For example, a thesaurus could be used todetermine other topics (e.g., synonyms) that are closely related to theidentified topics or that are conceptually similar to the identifiedtopics.

[0055] For the sake of clarity, the foregoing references to “revising”the target document are a figurative aid in understanding the use ofadditional information that is not literally within the target document.Those skilled in the art will recognize that the target document neednot be actually revised to make use of this additional information.

[0056] C. Conclusion

[0057] The foregoing description of preferred embodiments of the presentinvention provides illustration and description, but is not intended tobe exhaustive or to limit the invention to the precise form disclosed.Modifications and variations are possible in light of the aboveteachings or may be acquired from practice of the invention.

[0058] The scope of the invention is defined by the claims and theirequivalents.

What is claimed:
 1. A method for determining if an advertisement isrelevant to a target document, the method comprising: identifyingtargeting information for the advertisement; analyzing the content ofthe target document to identify a set of one or more topics for thetarget document; comparing the targeting information to the set of oneor more topics to determine if a match exists; and determining that theadvertisement is relevant to the target document if the match exists. 2.The method of claim 1, wherein the advertisement belongs to anadvertiser, and wherein identifying targeting information comprisesreceiving a list of topics from the advertiser.
 3. The method of claim1, wherein identifying targeting information comprises generating a listof topics by analyzing content of the advertisement.
 4. The method ofclaim 1, wherein analyzing the content comprises identifying a set ofone or more topics by calculating a term vector for the target documentbased on text within the target document.
 5. The method of claim 4,wherein terms in the term vector are assigned weights based on thefrequency with which the terms appear in the text of the targetdocument.
 6. The method of claim 4, wherein terms in the term vector areassigned weights based on the infrequency with which the terms appearacross a collection of documents.
 7. The method of claim 4, wherein theset of one or more topics contains terms whose weight exceeds a definedthreshold.
 8. The method of claim 4, wherein the set of one or moretopics includes a defined number of terms with the highest weights amongthe terms of the term vector.
 9. The method of claim 1, whereinanalyzing the content comprises identifying a topic based on otherportions of a collection of which the target document is a part.
 10. Themethod of claim 1, wherein analyzing the content comprises identifying atopic based on one or more queries that yield a reference to the targetdocument.
 11. The method of claim 1, wherein analyzing the contentcomprises: determining at least one similar document to the targetdocument; supplementing content of the target document with the contentof the similar documents; and analyzing the supplemented content of thetarget document to identify a topic.
 12. The method of claim 11, whereindetermining at least one similar document comprises determining that adocument is similar if it contains a reference to the target document.13. The method of claim 11, wherein determining at least one similardocument comprises determining that a document is similar if the targetdocument contains a reference to the document.
 14. The method of claim11, wherein supplementing includes replacing at least a portion of thecontent of the target document with at least a portion of the content ofthe at least one similar document.
 15. The method of claim 1, whereinanalyzing the content comprises: identifying a description of the targetdocument used by another document that references the target document;and analyzing the content of the description to identify a topic for thetarget document.
 16. The method of claim 1, wherein analyzing thecontent comprises: identifying a description of the target document usedby another document that references the target document; supplementingthe content of the target document with the description; and analyzingthe supplemented content of the target document to identify a topic forthe target document.
 17. The method of claim 1, wherein analyzing thecontent comprises: classifying the target document into a category; andidentifying a list of one or more topics for the target document basedon the category.
 18. The method of claim 17, wherein meta-informationassociated with the target document is used to classify the targetdocument into a category.
 19. The method of claim 18, wherein themeta-information includes information from another document thatcontains a reference to the target document.
 20. The method of claim 18,wherein the meta-information includes information from another documentto which the target document refers.
 21. The method of claim 19, whereinthe information from another document includes meta-informationassociated with the other document.
 22. The method of claim 1, whereincomparing the targeting information to the topic comprises comparing thetargeting information to the topic or a related topic to determine if amatch exists.
 23. The method of claim 14, wherein the related topic is asynonym of the topic.
 24. The method of claim 14, wherein the relatedtopic is conceptually similar to the topic.
 25. The method of claim 1,wherein the target document is a target web page.
 26. The method ofclaim 25, wherein analyzing the content comprises: analyzing termswithin the target web page and including them in the set of one or moretopics if the frequency with which they appear in the target web pageexceeds a threshold value.
 27. The method of claim 26, furthercomprising: determining terms that are related to one or more topics inthe set; and supplementing the set to include the related terms.
 28. Themethod of claim 25, wherein analyzing the content comprises analyzingterms within a title of the target web page and including them in theset of one or more topics if the frequency with which they appear in thetitle exceeds a threshold value.
 29. The method of claim 25, whereinanalyzing the content comprises: calculating a term vector for thetarget web page based on text within the target web page; andidentifying a list of one or more topics based on the term vector. 30.The method of claim 29, wherein terms in the term vector are assignedweights based on the frequency with which the terms appear in the targetdocument.
 31. The method of claim 29, wherein terms in the term vectorare assigned weights based on the infrequency with which the termsappear across a collection of web pages.
 32. The method of claim 29,wherein the set of one or more topics includes terms whose weightexceeds a defined value.
 33. The method of claim 29, wherein the set ofone or more topics includes a defined number of terms with the highestweights among the terms of the term vector.
 34. The method of claim 25,wherein analyzing the content comprises: determining at least onesimilar web page to the target web page; revising the content of thetarget web page by supplementing it with the content of the similar webpage; and analyzing the revised content of the target web page toidentify a set of one or more topics.
 35. The method of claim 34,wherein supplementing includes replacing at least a portion of thetarget web page content with at least a portion of the similar web pagecontent.
 36. The method of claim 34, wherein determining at least onesimilar web page comprises determining that a web page is similar if itcontains a link to the target web page.
 37. The method of claim 34,wherein determining at least one similar web page comprises determiningthat a web page is similar if the target web page contains a link to theweb page.
 38. The method of claim 34, the web page is contained in ahost, and wherein determining at least one similar web page comprisesdetermining that a web page is similar if it is contained within thesame host as the target web page.
 39. The method of claim 34, whereinthe web page is contained in a host, and wherein determining at leastone similar web page comprises determining that a web page is similar ifit is stored within a subdirectory of related pages on the same host asthe target web page.
 40. The method of claim 25, wherein analyzing thecontent comprises: determining anchor text corresponding to the targetweb page; revising the content of the target web page by supplementingit with the anchor text; and analyzing the revised content of the targetweb page to identify a set of one or more topics.
 41. The method ofclaim 40, wherein supplementing includes replacing at least a portion ofthe target web page content with at least a portion of the anchor text.42. The method of claim 40, wherein supplementing includes replacing thetarget web page content with at least a portion of the anchor text. 43.The method of claim 25, wherein analyzing the content comprises:classifying the target web page into a category; and identifying a listof one or more topics for the target web page based on the category. 44.The method of claim 43, wherein meta-information associated with thetarget web page is used to classify the target web page into a category.45. The method of claim 44, wherein the meta-information includesinformation from another document that contains a reference to thetarget web page.
 46. The method of claim 45, wherein the informationfrom another document includes meta-information associated with theother document.
 47. The method of claim 44, wherein the meta-informationincludes anchor text corresponding to the target web page.
 48. Themethod of claim 25, wherein the advertisement belongs to an advertiser,and wherein identifying targeting information comprises receiving a setof one or more topics from the advertiser.
 49. The method of claim 25,wherein identifying targeting information comprises generating a set ofone or more topics based on content of the advertisement.
 50. The methodof claim 25, wherein identifying targeting information comprisesgenerating a set of one or more topics for the advertisement based ontext of queries on a search engine that yield a result that links to aweb page on a web site to which the advertisement links.
 51. A methodfor determining if an advertisement is relevant to a target web page,the method comprising: identifying targeting information for theadvertisement; generating a set of one or more topics for the target webpage based on the text of queries on a search engine that yield a resultthat links to the target web page; comparing the targeting informationto the set of one or more topics to determine if a match exists; anddetermining that the advertisement is relevant to the target web page ifthe match exists.
 52. A method for determining if an advertisement isrelevant to a target web page, the method comprising: identifyingtargeting information for the advertisement; generating a set of one ormore topics for the target web page based on a search query history ofone or more users who visit the target web page; comparing the targetinginformation to the set of one or more topics to determine if a matchexists; and determining that the advertisement is relevant to the targetweb page if the match exists.
 53. The method of claim 52, wherein thesearch query history is based on users who visited the target web pagewithin a given time period.
 54. The method of claim 53 wherein the giventime period is the last Y minutes, wherein Y is a predefined term.
 55. Amethod of serving to a target web page a relevant advertisement, themethod comprising: receiving a request for an advertisement that isrelevant to the target web page; analyzing text of the target web pageto identify a set of one or more topics corresponding to the target webpage; determining advertisements that are associated with a topic thatappears in the set; and providing at least one of the identifiedadvertisements in response to the request.
 56. The method of claim 54,wherein determining advertisements comprises determining advertisementsfor which keywords have been specified that correspond to a topic thatappears in the set.
 57. Apparatus for determining if an advertisement isrelevant to a target web page, the apparatus comprising: means foridentifying targeting information for the advertisement; means foranalyzing content of the target web page to identify a set of one ormore topics for the target web page; means for comparing the targetinginformation to the set of one or more topics to determine if a matchexists; and means for determining that the advertisement is relevant tothe target web page if the match exists.
 58. A method for determining ifan advertisement is relevant to a target web page, the methodcomprising: a step for identifying targeting information for theadvertisement; a step for analyzing the content of the target web pageto identify a set of one or more topics for the target web page; a stepfor comparing the targeting information to the set of one or more topicsto determine if a match exists; and a step for determining that theadvertisement is relevant to the target web page if the match exists.59. Apparatus for determining if an advertisement is relevant to atarget web page, comprising: at least one memory having programinstructions, and at least one processor configured to execute theprogram instructions to perform operations of: identifying targetinginformation for the advertisement; analyzing content of the target webpage to identify a set of one or more topics for the target web page;comparing the targeting information to the set of one or more topics todetermine if a match exists; and determining that the advertisement isrelevant to the target web page if the match exists.